<html>
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        //parseInt整数
        //parseFloat浮点数
        console.log(parseInt(""));       //NaN  
        console.log(parseInt(3.14));     //3
        console.log(parseInt(4.14));     //4
        console.log(parseInt("abc123")); //NaN
        console.log(parseInt("123abc")); //123
    </script>
</body>
</html>